Vintage railway film Power to stop 1979

This vintage railway film was produced by British Transport Films in 1979. At the time, the majority of railway vehicles were fitted with cast iron brake blocks which, although relatively cheap to produce, wear rapidly in service and need frequent replacement. The film shows how an investigation into some of the problems associated with these brake blocks led to the development of a new type, with a higher phosphorus content which gives better performance and has a longer life.